Cataclysm was originally an expansion pack for Homeworld, requiring the original game to run. However, Barking Dog made such large changes to the game engine and also made the game bigger (17 missions to Homeworld's 16), so impressing Sierra that they decided to change it to a stand-alone release.

The game was critically acclaimed on release, with its improved interface (including being able to issue combat commands on the sensor manager screen) and the time-skip facility being particularly welcomed.

While the canonicity of Cataclysm has been disputed by fans for years, Dan Irish – the Homeworld 2 Executive Producer – said that "the events of Cataclysm are not mentioned in Homeworld 2, but they are accepted as having occurred".[2][3] However, the new IP owners, Gearbox Software, has stated that they do not consider Cataclysm to "exactly" be canon.[4]

Cataclysm's source code was lost when Barking Dog was acquired by Rockstar Games. Without the source code, it has not been possible for Gearbox to re-release the game as with the Homeworld Remastered project. Gearbox have indicated that if the code is found, they would consider the possibility. They have also noted that Blizzard Entertainment now own the Cataclysm video game trademark (for their World of WarCraft expansion of the same name), so the game would have to be renamed for a new release.

On 22nd June 2017, Gearbox Software and GOG announced they are reselling Homeworld: Cataclysm under the name Homeworld: Emergence. The reason is that Blizzard Entertainment owns "cataclysm" as a trademark (per World of Warcraft: Cataclysm).[5] However, this only changes a few references to "Cataclysm" in the game, as the executable is still "cataclysm.exe".

Contents

The war for Hiigara has left the Galaxy in turmoil. The past fifteen years have seen the birth of new possibilities ... and the festering of old grudges. The once dominant Taiidan Empire has fractured under the strain of civil war. The new Taiidani Republic tries to hold old territories together, while forces loyal to the old Emperor lurk in the new bandit kingdoms, waiting for their chance to strike back.

While the Taiidani struggle between past and future, the Kushan people have established themselves on Hiigara. Building new cities. Repairing the damage done by the final battle for their homeworld.

Even a fragile peace has its politics. The Kiith council has been reestablished, and the future of Hiigara is now debated amongst the gathered Kiith-Sa. Even amongst equals, there are power struggles.

The Mothership still orbits high above Hiigara. Pressed into the role of shipyard, she now builds new carriers to the specifications of each individual Kiith. The need for new ships and the crews to man them is a desperate one. Military and economic pressure on the new Hiigarans is intense.

Resources and technology are at the command of the council. Kiith with little or no political power have been forced to purchase technology from the Bentusi and other races. Hiigaran ships of exotic design now seek their future amongst the stars.

The war for Homeworld is over now. But the galaxy remains a dangerous place...

Hearing the radio call, the Kuun-Lan returns to Hiigara to assist in the defence of their homeworld. It helps the Nabaal by destroying some enemy fighters attacking the friendly Ion Cannon Frigates, before dealing with enemy Resource Collectors.

After destroying the resourcing operation, the Proximity Sensor grid comes under attack from some Interceptors and Multi-Gun Corvettes. These are dispatched quickly by the Kuun-Lan's own Acolytes and ACVs, before the tide of battle is turned in favour of the Hiigarans. Sensing this, the enemy Heavy Cruiser flees, but is dispatched by the Kuun-Lan's defensive fleet.

Instead of any thanks from Kiithid, the Somtaaw receive orders to return to the job of helping retrieve wrecks and collect the dead from the battlefield. The task leads the Kuun-Lan to its next assignment at the edges of Hiigaran space to rescue the stranded Bushan-Re, a Destroyer in the service of Kiith Manaan and whose hyperdrive is off-line.

The Kuun-Lan comes to the destroyer's aid, only to discover the presence in the region of Turanic Raiders, intent on destroying the Bushan-Re, who now requires an escort as well as a repair crew. Even after the Turanic Raiders are initially defeated, they reveal a new and rumored "mimicking" technology, which is shortly thereafter copied by the Somtaaw. The Kuun-Lan bravely continues to defend the Bushan-Re and finally finish the repairs to the hyperdrive. Unable to assist in the battle, the vulnerable destroyer then departs, wishing luck to the Somtaaw.

Continuing to defend against the attacking forces, the Kuun-Lan prepares to leave when Fleet Intelligence detects a strange artifact emitting a weak beacon. Fleet Intelligence orders the recovery of the artifact before the Turanic Raiders find it. The Somtaaw send a single escorted worker to recover the derelict while fending off Turanic Raider attempt to do the same. The derelict is retrieved and brought back to the Kuun-Lan, which then makes the jump to hyperspace.

The Kuun-Lan's science team finds that it is unable to examine the derelict properly and Fleet Command requests of the Somtaaw Kiith-sa that he allow them to seek out assistance. Somtaaw-sa forbids this and demands that the Kuun-Lan's discovery remain completely secret. Instead they recommend the Somtaaw to seek out the Clee-San, the Somtaaw's lone science vessel.

The Kuun-Lan arrive at a designated rendezvous point to meet with the Clee-San but discover that it has been captured by Turanic Raiders who are intent on stealing valuable Somtaaw technology such as the Acolyte Drive. Using the captured mimicking technology, the Kuun Lan is able to make it past a large field of mines surrounding the Clee-San and communicate with it. They discover that a Turanic carrier fleet will be arriving soon to take possession the science vessel and its technology. If the Somtaaw are going to rescue the Clee-San they must do so soon.

An all out assault by a Somtaaw fleet manages to break the defenses around the Clee-San, allowing the Somtaaw a chance to escort the ship to the Kuun-Lan. They barely escape in time to avoid a heavily armed Turanic carrier fleet. Jumping out of range of the Turanic fleet the Somtaaw begin to examine the mysterious derelict in earnest which they discover to be encoded in some strange, alien language and that it is covered in some sort of organic matter. Research continues as the Kuun-Lan moves out of range.

The Kuun-Lan is forced to perform an emergency exit of hyperspace. The hanger and science modules are quickly succumbing to some kind of disease and the scientists struggle to keep it under control. When they are unable to do so any longer they sacrifice themselves by demanding Fleet Command to cut them from the main hull. Separated from the main vessel, they drift off into space, their inhuman screams haunting the imagination.

Shortly after the Kuun-Lan begins to rebuild its lost modules and sends the Clee-San and an escort of ten acolytes to examine the situation. They are met by the ejected modules who are now covered in the same organic matter that once covered the derelict. Soon afterwards, the module broadcasts a chilling greeting: "We live...." The Clee-San and its escorts are attacked by a mysterious beam of energy which leaps from vessel to vessel and forces them to succumb to the same thing that attacked the modules. Then the impossible happens: the acolytes fly against the Kuun-Lan.

Panicking, the Somtaaw attempt to hold off the attackers while scrambling for whatever little information they have on the derelict they took aboard. As they do this their Turanic pursuers arrive along with a Taiidan Heavy Cruiser, and demand the Clee-San. Though Fleet Command tries to warn them off the Turanics believe it a ploy to frighten them away and head for the succumbed ships anyway. The Somtaaw continue to fight off the infected attackers, each vessel more and more powerful as their enemy absorbs more and more technology.

Meanwhile, the Turanic fleet arrives at the Clee-San and is delighted to find it and the Kuun-Lan research module, without giving a thought to why it is separated from the Somtaaw command vessel. In seconds they themselves are infected by the strange disease and too turn towards the Kuun-Lan. Within minutes they are upon the Somtaaw who realized they have no more time to spare. With just enough information based on the behavior of the infected ships to make a basic plan of action they make an emergency jump and escape from the battlefield.

In hyperspace the Somtaaw dubb the infection The Beast and determine that it is some kind of biomechanical being that binds to vessels and turns organic matter into living circuitry. Unable to discern more the Somtaaw head towards an area where a Bentusi Exchange was recently spotted, hoping to find more information from the ancient race. To their dismay they find the Bentusi instead under attack by the very enemy they were hoping to seek help against and watch as Beast ships surround the tradeship, damaging it greatly.

The Kuun-Lan acts to defend the Bentusi and shortly after another fleet arrives, hearing a Bentusi distress call. This time it is a Manaani fleet, led by the Caal-Shto. The Somtaaw, realizing the Manaani know nothing of this Beast seek now to protect the Manaani from themselves and watch as the Bentusi tradeship succumbs to attack and destroys itself rather than be infected. Destroying the remaining Beast fleet the Somtaaw partially repair the Caal-Shto, the only remaining ship in the Manaani fleet and begin to voyage on standard drives.

Hoping to escape to through the Kadiir Nebula they come upon a secret Imperialist station guarded by a large task force. Attempting to sneak by the station the Somtaaw use recons to navigate a safe path but are eventually discovered by the Imperialists who attempt to stop the Somtaaw and Caal-Shto from escaping into a small wormhole or slipgate. Evacuating the Caal-Shto, whose crew vows to notify the Daiamid of the Beast, the Kuun-Lan holds off the Imperialists long enough to escape.

It is then that they come across a convoy of Republican refugees fleeing from a supernova who are under attack by a cruise missile equipped with a bioweapon that is immediately recognized by the Somtaaw as the Beast. After shielding the refugees from the attack the Somtaaw learn that the Republicans believe the cruise missiles to be an Imperialist weapon. With this information the Kuun-Lan sets out to investigate these claims by meeting with a Republican spy deep within Imperialist territory.

When they come to meet the spy however they find him pursued by Imperialists who have discovered his identity. After rescuing him the spy reveals to them that the weapons are believed to have been developed at Gozan IV and that to get there they must recover some Imperialist vessels that will have the required codes to get past the planetary defenses and that two resourcers in the area should do the job.

The spy gives the Somtaaw the coordinates of the Imperialists and the Kuun-Lan begins its pursuit. As soon as the Taiidan spot the Somtaaw however they began to charge their hyperdrive, outnumbered and outgunned by the surprise attack. They are unable to escape however and the Somtaaw capture a vast number of Imperialist ships, jumping away to Gozan IV.

Carefully infiltrating the area near Gozan IV the Somtaaw lay outside the range of Taiidan proximity sensors in the area and use the captured resourcers to sneak past the sensors, which recognize the ships as Imperialist vessels. Heading for the surface the resourcers carry an assault team, which upon landfall storms the Taiidan research facilities.

There the Somtaaw manage to recover vital information before they are discovered and attacked by the planetary defenses. This information reveals the Taiidan indeed did attempt to use the Beast as a bioweapon but failed miserably at their attempt though they did come up with a way to contain infections. With this information they escape and come to rest at Koreth's Rift.

At Koreth's Rift the Somtaaw discover something amazing: a derelict weapon they believe to be a Siege Cannon and a weapon they can reverse engineer for their own benefit. They send out a worker team to salvage the cannon but find that there is an Imperialist-Turanic force in the region intent on destroying or capturing the Kuun-Lan. As they race to install the cannon the Somtaaw are aided by the quick arrival of the Caal-Shto who promise aid. But when Turanic and Imperialist vessels attack the Caal-Shto they meet instead an infected vessel who is quickly assisted by a mysterious mothership-class vessel. In horror the Somtaaw recognize the mothership as their missing modules but with a new hull built around them. Fleet command is put into a state of disbelief when the Beast begins to speak directly to the Kuun-Lan.

Realizing their chance as the Imperialist and Turanic forces are decimated the Somtaaw fire their siege cannon, hoping to destroy the Beast. Remarkably the Beast survive the blast without injury and proceed to attack the Kuun-Lan. Realizing they are cornered and outnumbered the Somtaaw escape into hyperspace. Hoping to notify the Faal-Corum, another of the Somtaaw command ships, about the Beast as the Caal-Shto failed to reach Hiigara the Kuun-Lan heads to a known mining site but find the Faal-Corum under attack.

After rescuing the Faal-Corum and enduring friendly fire due to the Faal-Corum's initial belief the Beast vessels belonged to the Kuun-Lan the Faal-Corum apologizes and agrees to warn the Daiamid and departs at once after helping the Kuun-Lan decode the data recovered from the derelict. It is at this time that the scientists aboard the Kuun-Lan finally make a breakthrough in the derelict and discover it was originally part of an ancient million-year old alien vessel known as the Naggarok that was infected during the test of a powerful hyperdrive.

The crew who realized they could not stop the Beast instead disabled their vessel to the point of being defenseless and immobilized. Unfortunately the Naggarok's automatic systems sent out a beacon pod, one that contained a single fragment of the Beast. Now, Fleet Command hopes to locate the Naggarok to learn more about the Beast and how to defeat it. They believe the information can be found amongst the Turanics who have long charted the Galaxy and may have necessary information regarding gravitational drift to apply to the Naggarok's last known location.

When the Kuun-Lan arrives at a Turanic outpost however they are greeted by first silence and then fire. Realizing they have no choice but to fight the Kuun-Lan forces the Turanics to negotiate and strike a deal that allows them the necessary information. Heading off for the believed location of the Naggarok the Kuun-Lan takes the remaining Turanics on board as prisoners and heads off.

As the Somtaaw travel through hyperspace, some of the Turanic prisoners escape and set a bomb off within the Kuun-Lan, heavily damaging it and forcing it out of hyperspace into an ambush. There the Kuun-Lan is met by an Imperialist fleet and is barely able to defend itself, its fighters damaged while in dock and the Kuun-Lan burning across several decks.

They are saved by the arrival of a Hiigaran fleet sent by the Daiamid following the Faal-Corum's return to Hiigara. Placing the new fleet directly under the Kuun-Lan's command the Hiigaran fleet pushes back the Imperialists and destroys their fleet. Now with enough firepower to turn the tide the Kuun-Lan continues its journey, heading for the estimated location of the Naggarok.

When they arrive they are surprised to learn the Imperialists have already arrived and are repairing the Naggarok. The Kuun-Lan professes this is mad but are met by scorn and violence. Knowing they still need information on the Beast the Somtaaw send a Mimic into the Naggarok to recover needed information. Then, when the Naggarok is repaired they manage to escape before the allied fleet of the Beast and Imperialists descends upon them.

Knowing they need help they again try to find the Bentusi and enlist their aid. Upon meeting with the Bentusi they discover that their old allies will not answer them. Following the Bentusi they discover an enormous slipgate through which the Bentusi are fleeing to another galaxy. Immediately the Kuun-Lan attempts to stop them, and begin destroying the nodes circling the slipgate. The Bentusi, terrified of the Beast and afraid of their escape being prevented, meet the Somtaaw's interference with vicious fire from the tradeships and their ion fighters, dubbed "super acolytes" by the Somtaaw. Realizing they cannot hope to triumph over Bentusi firepower Fleet Command tries to guilt them into helping them. As hundreds die the Bentusi begin to see that they have let their fear drive them and stand down, after a long battle and the destruction of the gate.

The Bentusi provide the Somtaaw with necessary upgrades to the ancient siege cannon, allowing it to damage Beast vessels, despite their ability to rapidly "grow" replacement parts. Fleet Command and Fleet Intelligence, hoping to test the weapon's effectiveness and to wipe out the Beast Mothership in one strike head for the Clee-San's last known location. There they find it and are able to obliterate its escort fleet and pacify it, using a single siege cannon blast at half power.

The Clee-San's defenses destroyed and the Beast self on board neutralized the Somtaaw board it using a crew of two workers and send out a false distress beacon to draw the Beast Mothership to the Clee-San, which they then destroy. When the Mothership arrives the Somtaaw obliterate it with a crushing blow of the siege cannon and jump to hyperspace, ready to meet up with the allied fleet positioned at the Nomad Moon, where an experimental weapon is being tested by the Taiidan Republic to destroy the Beast and their Imperialist allies.

There they find the Taiidan Republican fleet nearly destroyed (though it is possible to save the last Republican carrier from destruction), the Beast near victorious, and the weapon station known as the Nomad Moon succumbed to the Beast. Realizing it will be up to them alone to defeat the Beast the Kuun-Lan and its escorts fight a desperate battle to destroy the Moon but are surprised to learn the mysterious weapon used is a repulsor field which repels all attacks. Only through the use of Leeches do the Somtaaw manage to disable Nomad Moon.

Yet just as victory seems possible an Imperialist fleet arrives, along with a Beast fleet from the other side, a deadly pincer movement that could obliterate the Kuun-Lan. To make matters worse, the Naggarok proves to be a weapon in its own right, despite being what is essentially a research vessel for a long gone race. Armed with an incredibely powerful version of the resourcing tool known as the Phased Disassembler Array the Naggarok is able to disintegrate any vessel it finds. Now fighting on three fronts and watching as the Naggarok tears through the allied fleet at amazing speeds the battle seems hopeless.

The Somtaaw are able to heroically hold off the Beast assault however, successfully repelling the Beast reinforcements approaching from one side of their fleet and managing to stand their ground as the Imperialists draw closer. Even more importantly, the timely arrival of a Bentusi tradeship brings certain victory when they grant the Kuun-Lan the ability to construct super acolytes.

Then, impossibly, the Imperialists turn on their allies after realizing the word of the Beast amounts to nothing as they discover the arrival of the Bentusi, who the Beast claimed were no longer a threat. Abandoned the Beast fight desperately on, only to be obliterated by the Somtaaw forces at last. Now, with the Naggarok destroyed, the end of the war with the Beast seems near.

Celebrating the Somtaaw's victory the Daiamid grants them the honored title of "Beast Slayer" and welcome them with respect. The Somtaaw then set out to finish the job and destroy the rest of the Beast strains, a task they dutifully complete in little time.

Note: It is possible to stop the complete destruction of the Republic Taiidan's fleet from the Beasts. The Nomad Moon fleet consists of three carriers. The first carrier was destroyed shortly after the Nomad Moon fell to Beast control (in a cut scene before the Somtaaw reached the base). The second carrier had a brief dialogue sequence but it will be destroyed as well. The third carrier will still be alive when the mission starts. A player's first inclination is to help the fleet below the mothership to fight off the Beast, but that fleet is doomed regardless. If you want to save the carrier you'll have to quickly send anything smaller than dreadnoughts (they'll be too slow) to the carrier's location. If you do this correctly you'll be able to have most of your fleet at the carrier's location before the beast destroys it. Have your dreadnoughts guard the mothership and have the mothership move towards the carrier. Once the carrier is safe from the main beast force the beasts will not send any more heavy attacks at the carrier (but have your mothership guard it just in case). If the carrier is saved then Republican reinforcements will keep hyperspacing in throughout the entire duration of the mission and this will provide great support especially when attacking the moon. If you do not save it then you'll eventually have to take on the beast by yourself

Numerous small changes and fixes were added, such as the ability to toggle 8X time compression. This quickens the typically slow 'post battle' harvesting of resources and building after a level is finished. Ship upgrades were added, improving armor and adding new abilities, and command ships and carriers were given the ability to add external modules for ship research and larger fleet support. Ship experience levels were also included, gaining up to four levels through combat boosting all of their abilities which carried over in campaign missions. Fuel was completely eliminated from the game, so players didn't have to constantly monitor their corvettes and fighters for low fuel levels. In addition, the sensor display could be used to issue attack orders to friendly units—a very handy feature not included in the original. The game also now includes adjustable difficulty levels from very easy to very hard. Another welcome addition was a full cast of voice actors for every ship with semi-unique dialog for each of them in various situations, making it much easier to identify which ship was doing what or complaining about heavy damage. The original Homeworld had three men voicing everything, which was unfortunately carried over to Homeworld 2, making it much less immersive and nearly impossible to figure out which ship was in trouble from the dialog alone.

Although slow and methodical in its movement, the command ship is capable of delivering a frightening array of weaponry. Namely, it is capable of deploying an epic scale cannon in battle that can completely eradicate an enemy fleet at extreme range—capital ships and all. As such, the command ship is less of a liability and more of a knockout punch, especially late game.

The game is smaller in scale than its predecessor and streamlines the selection of ship types by reducing the number of different ships while enhancing the versatility of the remaining ones. Processors, for example, which seemed to be the modernized version of the resource Controller from Homeworld, were greatly improved. They were given medium-strength weapons to defend from smaller craft, repair beams to heal damaged resource collectors, and four (rather than one) pads to dock with resource collectors. The game's resource collectors, smaller yet more versatile, perform the same functions that they did in the original Homeworld. However, these craft, when upgraded, are capable of capturing enemy vessels and repairing friendly vessels, esentially being a hybrid of Resource Collectors, Support Frigates and Salvage Corvettes.

One of the best aspects of the game compared to the other Homeworlds. While they have only 3 men voicing all of the ships other than the Mothership and a very small selection of campaign character voices, Cataclysm has a different voice actor for every ship type and more distinct dialogue for each to make them even more unique, as well as a larger number of campaign dialogue voices. On top of the improved immersion this also makes it easier to tell which ship is calling for help when they're engaged in fleet combat.

Cataclysm is able to run on Windows 7, but it requires installation of the patch.

Rarely, the game can crash when the Mission 05 cinematic finishes. Reloading the game from the last save will bypass this bug

If the player quits out of the game and reloads a save taken before ending any of the missions that don't involve a hyperspace jump, there is a possibility that the game will perform the letterbox cut scene bars, but no fade occurs, which prevents the game from proceeding. This can happen without exiting the game.

This bug can be solved simply by using Alt+Shift+Tab to minimise the game, then clicking the icon for the game to reload it. This appears to "jump start" the fading sequence and the game will progress normally.

This bug does not occur on missions where the player exits via a hyperspace jump.